If you’re unfamiliar with aquaculture, or fish farming, it might be time to wade into its murky waters for a better understanding. It’s widely criticised by conservationists, but it’s also the reason wild fish catches have not increased since the early 1990s. The rise in fish consumption since then has been met by the increase in fish farming, so surely that’s a good thing? But what is aquaculture exactly? And why should we care?
Here are 10 things every South African should know about this growing practice:
- Since 2016, more than 50% of fish consumed worldwide has come from fish farms. That’s a massive increase from the 10% of total production it was 30 years ago. This is due to the dwindling fish populations in the ocean due to overfishing and the increased consumption of fish, which now accounts for about 17% of all animal protein consumed by the global population. The average person now eats almost twice as much seafood as half a century ago. Our consumption of farmed fish in South Africa, however, is much less than the global average. With some experts saying it’s probably not even 10%, as our own aquaculture industry is highly regulated.
- As commercial fishing operations continue to strip the world’s oceans of life, fish farming is increasingly seen as a way to meet the world’s growing demand. The global wild fish catch has remained relatively constant at around 90 to 95 million tonnes per year since the early 1990s. Fish farming, on the other hand, is growing very rapidly, from 1990 until 2015 it has increased 50-fold to over 100 million per year. Aquaculture production has absorbed almost all of the growth in global demand in recent decades and will continue to play a critical role in protecting wild fish populations as demand for seafood continues to rise.
- But there are drawbacks. One of the biggest criticisms of aquaculture is that carnivorous fish such as salmon and tuna are fed wild-caught fish – so it still depletes the ocean’s stocks. While some farmed fish can live on diets of corn or soy, top-level carnivores (most salmon species) depend on fish feed of which a portion is usually derived from wild-caught fish such as anchovies and herring. Time Magazine reports that it takes 4.5 kg of ocean-caught fish to produce 1 kg of fishmeal. ‘We have caught all the big fish and now we are going after their food,’ says the non-profit Oceana. Lots of research, however, is currently underway to replace fish meal with alternatives. In response to the serious shortage of fish meal, manufacturers have started substituting genetically engineered feed, like corn, soy, and algae.
- It’s believed escaped fish breed with wild fish and compromise the gene pool, harming the wild population. According to a Biznews article, up to two million runaway salmon escape into the wild each year in the North Atlantic region. The result is that at least 20% of supposedly wild salmon caught in the North Atlantic are of farmed origin. Embryonic hybrid salmon, for example, are considered by some experts to be far less viable than their wild counterparts, and adult hybrid salmon routinely die earlier than their purebred relatives.
- The ecological impact of the farms is considered by many experts to be high and varied. Daniel Pauly, professor of fisheries at the University of British Columbia in Vancouver, says they’re like floating pig farms. ‘They consume a tremendous amount of highly concentrated protein pellets and they make a terrific mess.’ Some believe farmed fish waste falls as sediment to the seabed in enough quantities to overwhelm and kill marine life in the immediate vicinity and for some distance beyond. It can also lead to the discharge of excess feed, antibiotics, and chemicals into the water, which causes algal blooms and dead zones. But a local fish farmer we spoke to believes the footprint of most farms is very limited, and sites for cage aquaculture are chosen specifically to dilute waste accumulation with currents or by wave action. ‘Cage farming actually attracts a multitude of other marine organisms that thrive on the biological waste and any uneaten food,’ he said. ‘An example is the cage farming of tilapia in Lake Kariba: the surrounding area teems with other fish species keen to share the bounty that to a small extent escapes the cages.’
But the massive amount of fish in one space can attract and harm wildlife, which get entangled in farm nets, harassed by acoustic deterrents, or hunted by larger species. In Saldanha, for example, where fish farms are currently in development, it’s feared the increased seal activity in the area will lead to further degradation of the wild fish stock.
As with most things, the way the industry, and specific farms, are run determines whether it’s a good idea or not. At their worst, fish farms can pollute the ocean, threaten native wildlife, produce unhealthy seafood, and harm local fishing communities.
- But there is hope of a more environmentally friendly future for aquaculture. These problems are undoubtedly challenging, but attempts are being made to overcome them. Fish farmers are starting to open inland fish farms that eliminate any chances of diseases spreading in the ocean. Scientists are also finding new ways to filter water and keep farmed fish in a contained, clean environment so antibiotics are not required. Advancements have been made in raising higher-maintenance ocean fish in land-bound, sterile environments, making on-land fish farms a viable option for some rarer, more expensive species. Fish farmers are using less fishmeal, or ground wild fish, than they were 20 years ago, further taking pressure off the overfished ocean.
- The thing is, there’s a big difference between marine aquaculture and inland aquaculture. Most marine aquaculture is of predatory species requiring high protein diets, and therefore fishmeal and higher amounts of noxious wastes. In South Africa, due to our rough seas, very few suitable marine aquaculture sites have been identified. There was a proposal to establish a salmon in Betty’s Bay, which was met with fierce opposition from the local population and petered out. The Langebaan Lagoon near Saldanha, however, has the natural protection from the sea and has been earmarked for development. This too has been met by much opposition and protests from the local people, particularly the fishermen.
Inland aquaculture, normally administered in dams, lakes and ponds focuses on species such as tilapia have less of an impact on the environment. There are different systems available to farmers but there are newly developed green water techniques, coming from the Far East, which are far more environmentally friendly than the local recirculating systems, which are heavy on energy and artificial feed. ‘There are many places in South Africa that are excellent candidate places for inland aquaculture,’ a local expert says. ‘Where water is plentiful, it can be used more than once and where constant flow is released (below state irrigation dams for example), it could be passed through large ponds first, and any overflow passed through artificial wetlands for cleaning, before being re-used downstream. No pumping, just gravity flow. This has been done in Botswana, for example, and this ensures zero pollutants reach the wild.’
- Freshwater aquaculture in Africa is finally coming of age, but only north of our borders. There are very few economically viable fish farms in South Africa, with the exception of the very successful trout and abalone sectors, but they’re common in Zambia, Mozambique, Uganda, and even Botswana. ‘Zambia, in particular, has a thriving aquaculture sector producing thousands of tons of good, healthy tilapia in competition to Chinese imports,’ the local expert we spoke to says. ‘A colleague recently completed a continent-wide tour of aquaculture facilities, and his findings reveal exciting developments in many countries, which suggest that Africa may, at last, be catching up with Asia in this regard. Egypt stands head and shoulders above other African countries, with an annual fish production of more than 750 000 tons.’
- So what’s the current situation in South Africa then? Compared with most other agricultural industries in South Africa, the farmed fish industry is in its infancy. Aquaculture has been identified as a critical industry, due to the popularity of its produce and the declining wild-caught yields world-wide. The suitable places on our coastline are limited and are already committed to other uses. Potential areas for marine farms, however, have been identified in Saldanha, Port Elizabeth and Mossel Bay. An approved plan to develop floating fish factories on an industrial scale in Saldanha has been met by local activists sounding the alarm that the project will potentially harm protected marine areas containing vulnerable species, lead to loss of fishing space and have negative impacts on tourism. Saldanha Bay lies at the mouth of Langebaan Lagoon, one of only three self-sustaining pure saltwater lagoons in the world.
There are ideas for other aquaculture projects in the… desert! It may sound strange but many dry places in Southern Africa have abundant groundwater that could be used for aquaculture and irrigation. The Kalahari-Karoo multi-layered aquifer stretches from eastern Namibia to southern Botswana and into western South Africa. ‘Passing such water through fish ponds, which are then fertilised to increase primary productivity and therefore natural food for the fish, makes perfect sense,’ a local fish farmer says. ‘After passing through the ponds, a percentage of the water could then be used for irrigation. Irrigation projects in desert areas benefit from the abundant sunshine and long growing period; the swathes of green around Upington are testimony to this.’
- So, what should we be eating? It’s widely recommended that we should eat fish twice a week. Fish are a lean, healthy source of protein – and the oily kinds, such as salmon, tuna, and sardines – deliver those omega-3 fats that help reduce your risk of depression, heart disease, and cognitive decline. But then there’s the question of sustainable seafood. Knowing what seafood is best for your health and the environment isn’t always easy. One suggestion is to use the mobile app Abalobi, which helps small-scale fisheries connect with consumers, allowing all activities along the value chain to track the fish and understand where it came from. Another option is to eat less seafood and get your omega-3’s from hemp, soy, or walnuts.